In PTL 1, integrated value data of carrier wave phases of a satellite signal on a positioning station side at a time point is acquired, and integer value bias included in an integrated value of the carrier wave phases of the satellite signal observed by the positioning station is estimated by associating the integrated value data of the carrier wave phases on the positioning station side at the time point with the integrated value data of the carrier wave phases on the base station side at a plurality of time points prior to the time point. In this way, it is possible to determine the integer value bias with a high accuracy in a short time.